Viruses, either those occurring in nature, or recombinant versions thereof, are used for vaccination and in the field of gene therapy. It is possible for many viruses or virus-like particles to safely and efficiently propagate in host cells. Several publications describe the purification of viruses from host cells, mostly concentrating on the use of specific chromatographic matrices for purification of the virus from a host cell lysate (see, e.g. U.S. Pat. No. 6,008,036). Other methods as described, for example, in U.S. Pat. No. 6,048,537 employ continuous sucrose gradient centrifugation, which delivers products with less antigen purity and requires further purification steps by centrifugation. Such methods also suffer from antigen aggregation, which can lead to a loss of viral antigen, or inhibit viral inactivation steps.
Viral aggregation can also inhibit the yield of chromatographic processes, which are time and cost intensive and difficult to adapt to a large scale production. It is therefore a goal of the present invention to provide a method to purify viruses, in particular from host cell samples, that is simple but still is capable of providing whole virus antigen fractions in high purity with reduced viral antigen aggregation.